Police are investigating shots fired outside Niles North High School in Skokie Friday night.

The shots rang out after a basketball game between Niles North and Evanston Township High School. Witnesses said the sound of gunfire sent people running as they left the game.

Officers were already at the school for the game. Police said that multiple people ran back into the school after hearing gunshots.

After an initial check of the school grounds, Skokie police officers did not find any evidence of a shooting. After the search was expanded, several shell casings were found in a driveway in the 9700-block of Le Claire Avenue. No victims or suspects were located.

According to a preliminary investigation, police said two groups of people congregated near the intersection of Payne Street and LeClaire Avenue. After shots were fired, the two groups scatted and left the scene.

Minor property damage was discovered on a tree on Le CLaire Avenue and on the south wall of the school building at 9800 Lawler Avenue, police said.